Shedding Light on Dawn Simulation Devices that gradually illuminate a sleeper’s environment prior to wake can be easier for patients to use than traditional bright light therapy. Though not as powerful, the simulators have shown promise for various sleep/wake disorders. By Regina Patrick, RPSGT, RST I n 1980, researchers found that exposing a person to high- intensity light caused an immediate but temporary cessation in melatonin production. 1 This finding led to the use of bright light to shift a person’s melatonin production, and consequently the sleep/wake cycles, to a more preferred time to treat circadian rhythm disorders or to improve the sleep of people who work the night shift or shift work or to lessen the effects of jet lag. 2-4 Bright light therapy is also used to treat seasonal affective disor- der (SAD) and other types of depression. 5 A recent outgrowth of light therapy research is dawn simu- lation research. Dawn simulators expose sleepers to a slowly increasing intensity of light for 30 minutes or more before awak- ening. Some dawn simulators also double as sunset simulators (that is, light begins to decrease gradually about 30 minutes before a set bedtime). Scientific interest in determining whether a more naturalistic exposure to light improves sleep and mood has shown some interesting findings. Dawn Simulation Research In 1989, Terman and colleagues were the first scientists to describe the effects of dawn simulation in humans. 6 In their study, participants with SAD were exposed to either simulated sunrise or both simulated sunset and sunrise for several days. After treatment, depressive symptoms either resolved or were greatly reduced in most participants. With treatment, the par- ticipants were able to fall asleep within 30 minutes of simu- lated sunset. The circadian rise and fall of melatonin production occurred earlier (ie, advanced phase shift) with sunrise simula- tion or with sunset plus sunrise simulation. Many researchers subsequently examined the impact of dawn simulation on different aspects of SAD. For example, some research indicates that dawn simulation improves sleep inertia, 7,8 cognition, 8 performance, 8 and mood 9 in people with SAD. In recent years, researchers have broadened their focus on the impact of dawn simulation on other disorders such as an advanced circadian rhythm in people with dementia and bipolar disease, and the results have been promising. In a Swiss study, patients with dementia were exposed to simulated sunset and sunrise (the simulator began decreasing the light intensity approximately 45 minutes before bedtime and increasing light intensity approximately 30 minutes before awakening); this 18 • sleepreviewmag.com SR_18_21_Dawn.indd 18 treatment decreased sleep latency and increased sleep dura- tion. 10 In a study comparing the effects of dawn simulation and bright light on symptoms of bipolar disorder and SAD, research- ers found that the response to dawn simulation was similar to that of bright light therapy, and therefore dawn simulation could be an alternative to bright light therapy. 11 Because dawn simulation causes an advanced phase shift, 12 the treatment may be beneficial for people with circadian rhythm disorders (such as delayed sleep phase syndrome or non-24-hour sleep-wake disorder) or who may experience jet lag. Similarly, pediatric populations such as teenagers who experience sleep phase delay may benefit from dawn simulation. Neal Owens, president of The Sunbox Company, says, “Parents with kids find that dawn simulation devices are extremely helpful. Most parents say it was the best investment they have made to get their kids up and going in the morning.” These populations have not yet been examined in depth in peer-reviewed journals. Dawn simulation, by allowing a slower awakening from sleep, may protect against early morning adverse cardiovascular events (for example, stroke or angina), which scientists suspect may be associated with sudden sympathetic activation. 13 More research is needed to examine to what extent dawn simulation may reduce the risk of early morning cardiovascular events. Similarities, Differences to Bright Light Therapy In a recent study, a Russian research team headed by Konstantin Danilenko found that bright light treatment may be more beneficial in relieving symptoms in people with severe SAD compared to simulated dawn therapy. 9 In their study, par- ticipants underwent bright light therapy and weeks later were crossed over to undergo simulated dawn therapy. After under- JUNE 2016 5/26/16 12:37 PM